Am I overreacting for not wanting my girlfriend to travel with her friends?

So my girlfriend has been talking about travelling with her friends for a while. I personally don’t want her to travel for a couple reasons.

First of all, we should be travelling together. That way, I can keep an eye on any funny business going on. How am I supposed to know if she’s flirting with other men when I’m not there?

Secondly, I think her friends are bad influences. I honestly think she should cut most of them off before they influence her to do something stupid.

Am I in the right here or am I overreacting?